The support is intended to maintain the cooking vessel at some distance from a burner of the stove. The burner must be close enough to the vessel to limit heat losses.
An evacuation of the flue gases generated by the combustion at the outlet of the burner is necessary. Thus the support is provided with openings so that the flow of flue gases is evacuated from the area located between the head of the burner and the vessel or the free area.
This system is satisfactory in that the flue gases do not stagnate in the free area and are evacuated towards the outside. The evacuation is even more effective that the openings are large and allow a good circulation of the flow of flue gases.
However, the flame is sensitive to the air flow penetrating into the free area by the openings. The flame can be extinguished by blowing, in particular by the wind during an outdoor stove use.
Large sized openings are advantageous to evacuate the flue gases, but offer little resistance to wind.